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With the global climate warming, extreme high - temperature weather is becoming more and more frequent. Traditional refrigeration equipment consumes a large amount of energy when adjusting the temperature and exacerbates the greenhouse effect. Against this background, Personal Thermal Management (PTM) technology has received extensive attention due to its energy - saving advantages. Among them, Passive Radiative Cooling (PRC) technology can release human body heat through radiation and has great application potential in the PTM field. However, most current radiative cooling materials only focus on outdoor cooling, ignoring the impact of indoor cooling on comfort and not fully considering the role of material structure in the radiation release in the mid - infrared band.
This study aims to develop a new type of radiative cooling fabric to achieve efficient indoor and outdoor cooling. By using electrospinning technology with an electrospinning device to prepare PVDF - PVP fabric, this technology is used to construct a full - scale structure with nano - level semi - interpenetrating pores, micro - level fibers and micro - level fiber - to - fiber voids. Combining with the selective emission characteristics of PVDF, the optical properties of the fabric in the solar wavelength band and the mid - infrared wavelength band are optimized to enhance its radiative cooling effect, providing an innovative and effective solution for personal thermal management and promoting the further development of this field.
This study has successfully developed a PVDF - PVP - based cooling fabric (FP - 12 - 6). Its design highlights the combination of full - scale structure and selective emission characteristics (Figs. 1, 2). Through the synergistic effect of nano - level semi - interpenetrating pores and micro - level fibers, the full - scale structure achieves a high reflectivity of 94% in the solar wavelength band and a reflectivity of only 6% in the mid - infrared wavelength band, effectively reducing heat absorption. The selective emission characteristics enable the fabric to have a radiation emission capacity of 81% in the atmospheric window band and maintain a radiation transmission capacity of 25% in the mid - infrared wavelength band, thus achieving efficient cooling in both indoor and outdoor environments. Experimental data show that this design not only improves the cooling efficiency but also broadens the application scenarios of cooling fabrics.
The theoretical calculation results strongly support the performance advantages of the FP - 12 - 6 cooling fabric. Specifically, the net cooling power of this fabric is as high as 60 W m⁻² in outdoor environments and 26 W m⁻² in indoor environments. These data are calculated based on a detailed radiative cooling model, fully considering the radiation characteristics of the fabric in different wavelength bands. Compared with traditional cooling materials, FP - 12 - 6 shows more superior cooling performance, especially under strong outdoor light conditions.
In actual outdoor tests, the cooling effect of FP - 12 - 6 has been significantly verified. When covered on the simulated skin, its temperature is 5.5 °C lower than that of the bare skin, and 5.0 °C and 4.3 °C lower than that of the PE film and PDMS film respectively (Fig. 5f). This result benefits from the high solar reflectivity and strong thermal radiation emission ability of the fabric, enabling it to maintain an excellent cooling effect under direct sunlight. In addition, the low mid - infrared reflectivity of the fabric ensures that the human body heat can be effectively dissipated through the fabric, further enhancing the cooling effect.
In the indoor environment, FP - 12 - 6 also shows good cooling performance. The test results show that the temperature of the simulated skin covered with FP - 12 - 6 is 1.4 °C lower than that of the PDMS film, slightly higher than that of the bare skin and the skin covered with the PE film (Fig. 5g). This indicates that even in an indoor environment without direct sunlight, FP - 12 - 6 can still provide a certain cooling effect through its selective emission characteristics, providing a new solution for indoor personal thermal management.
The FP - 12 - 6 cooling fabric not only performs well in cooling performance but also has its wearable performance comprehensively evaluated. The test results show that the fabric has good hydrophobicity, washing durability, wear resistance and excellent mechanical properties. In addition, its moisture permeability and air permeability also meet the daily wearing requirements, ensuring wearing comfort. The comprehensive performance of these properties makes FP - 12 - 6 a promising candidate for the next - generation intelligent personal thermal management fabric.
This paper has developed a full - scale structure cooling fabric with selective emission characteristics. Due to the synergistic scattering effect of semi - interpenetrating pores and randomly distributed fibers, the prepared FP - 12 - 6 fabric has a reflectivity of 94% in the solar wavelength band and a reflectivity as low as 6% in the mid - infrared wavelength band. In addition, the selective emission characteristics make the radiation emissivity of FP - 12 - 6 81% in the 8 - 13μm band and the radiation transmittance 25% in the 2.5 - 25μm band. Theoretical calculations show that this cooling fabric can achieve a net cooling power of 26 W/m² indoors and 60 W/m² outdoors. The actual results show that compared with the typical polydimethylsiloxane film, the cooling effect of FP - 12 - 6 can reach 5.5 °C in a sunny outdoor environment and 1.4 °C in an indoor environment. This work solves the compatibility problem between outdoor and indoor cooling and contributes to the next - generation more intelligent personal thermal management fabrics.
During the preparation process using electrospinning machine, the unique structure of the fabric was successfully formed, which laid a foundation for its excellent performance. Also, the precise operation of the electrospinning device in the experiment ensured the accuracy of fabric preparation.
Article source: DOI 10.1007/s40820 - 025 - 01713 - 4
